Backup automatically to a hard drive
This is more of a general software recommendation question, I believe, but one thinks it may be migrated in the future.
I'm familiar with one specific program known as Allway Sync which is for Windows (multiple versions) that can be configured to monitor/check specific locations. When a change is made to that/those locations, the files are then copied/synchronized with the configured destination.
I've used this specific function to prevent data loss for a client, which worked well. The program can also be configured to respond only to a specific device, which means you can exempt a different drive from storing the synchronized files, or alternatively, use multiple drives.
The free version will work until you've performed an undetermined number of backups/synchronizing actions at which point it will request payment. The cost is relative low for such a useful, powerful program.
There may be other similar types of programs available.